The research proposed here is designed to examine the cognitive, behavioral, and neurological outcomes at 6 years of age of approximately 75 very low birthweight (VLBW) children (i.e., less than 1,500 grams) who have been seen longitudinally since birth. Extensive medical, developmental and demographic data have already been collected on these children. The basic aims are twofold: to identify the critical factors that differentiate between normal and deviant functioning at 6 years; and to compare the outcomes of the VLBW cohort with that of a cohort of VLBW children born 5 years earlier, a group of LBW children born 5 years earlier, and a concurrently followed group of healthy fullterm children. To accomplish this, we plan to evaluate the 6 year olds using a variety of measures that will enable us to assess their overall level of cognitive development, as well as more specific areas of functioning, including perceptual organization, linguistic abilities, memory, reading and quantitative skills. In addition, we will be assessing the occurrence of behavior problems and neurological deficits in these children. Current functioning will be related to perinatal medical variables, neonatal neurobehavioral performance, electrophysiological indices of sensory and cerebral processing, and socioenvironmental data to allow us to assess the predictive validity of these early measures.